Inputs

List of inputs of EPW v5.8

Structure of the input data

title line

&inputepw

/

&inputepw

A adapt_ethrdg_plrn, a2f, amass, asr_typ, assume_metal

B band_plot, bands_skipped, bfieldx, bfieldy, bfieldz, bnd_cum, broyden_beta, broyden_ndim

C cal_psir_plrn, carrier, conv_thr_iaxis, conv_thr_plrn, conv_thr_racon, conv_thr_raxis, cumulant

D degaussq, degaussw, delta_approx, delta_qsmear, delta_smear, dvscf_dir, do_CHBB

E efermi_read, eig_read, elecselfen, eliashberg, elph, ep_coupling, epbwrite, epbread, epexst, ephwrite, epmatkqread, eps_acustic, epsiHEG, epwread, epwwrite, etf_mem, ethrdg_plrn

F fermi_diff, fermi_energy, fermi_plot, fila2f, fildvscf, filkf, filqf, filukk, filukq, fixsym, fsthick

G gap_edge

I imag_read, init_ethrdg_plrn, init_k0_plrn, init_ntau_plrn, init_plrn, init_sigma_plrn, interp_Ank_plrn, interp_Bqu_plrn, int_mob, io_lvl_plrn, iterative_bte, iverbosity

K kerread, kerwrite, kmaps

L lacon, laniso, lifc, limag, lindabs, liso, longrange, lpade, lphase, lpolar, lreal, lscreen, lunif, loptabs, len_mesh

M max_memlt, meff, mob_maxiter, mp_mesh_k, mp_mesh_q, muc, meshnum

N nbndsub, ncarrier, nc, nel, nest_fn, nethrdg_plrn, ngaussw, niter_plrn, nk1, nk2, nk3, nkf1, nkf2, nqf3, nq1, nq2, nq3, nqf1, nqf2, nqf3, npade, nqsmear, nqstep, n_r, nsiter, nsmear, nstemp, nswi, nswc, nswfc, nw, nw_specfun, nq_init

O omegamax, omegamin, omegastep

P phonselfen, plselfen, plrn, prefix, prtgkk, pwc

Q QD_bin, QD_min

R rand_nq, rand_nk, rand_q, rand_k, restart, restart_filq, restart_plrn, restart_step

S scell_mat, scell_mat_plrn, scr_typ, scatread, scattering, scattering_serta, scattering_0rta, scissor, selecqread, smear_rpa, specfun_el, specfun_ph, specfun_pl, system_2d, shortrange, step_wf_grid_plrn, start_mesh

T temps, tc_linear, tc_linear_solver, type_plrn

V vme

W wannierize, wepexst, wmax, wmax_specfun, wmin, wmin_specfun, wscut, wsfc

/

—- If wannierize = .true. the following input variable apply

auto_projections, dis_froz_min, dis_froz_max, iprint, num_iter, proj, reduce_unk, scdm_entanglement, scdm_mu, scdm_proj, scdm_sigma, wannier_plot, wannier_plot_list, wannier_plot_radius, wannier_plot_scale, wannier_plot_supercell, wdata

Back to Top

—- If a file named quadrupole.fmt is present in the running directory, the code will use quadrupoles to perform the interpolation of the electron-phonon matrix elements and dynamical matrices. The structure of the file is as follow:

atom   dir       Qxx         Qyy         Qzz         Qyz         Qxz         Qxy
1     1      XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX
1     2      XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX
1     3      XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX
2     1      XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX
2     2      XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX
2     3      XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX    XXXXXXXX
...

where XXXXXXXX have to be replaced by the value of the quadrupoles which can be obtained, for example, using the ABINIT software

Back to Top

a2f

Type

LOGICAL

Default

.false.

Description

Calculate Eliashberg spectral function, \(\alpha^2F(\omega)\), transport Eliashberg spectral function \(\alpha^2 F_{\rm tr}(\omega)\), and phonon density of states \(F(\omega)\). Only allowed in the case of phonselfen = .true.

Back to Top

amass(:)

Variable

amass(i), i=1,ntyp

Type

REAL

Default

0.0

Description

Atomic mass [amu] of each atomic type. If not specified, masses are read from data file.

Back to Top

asr_typ

Type

CHARACTER

Default

‘simple’

Description

Kind of acoustic sum rule that can be imposed in real space. Possible ASR are ‘simple’, ‘crystal’, ‘one-dim’ and ‘zero-dim’.

Back to Top

assume_metal

Type

LOGICAL

Default

.false.

Description

Assume we have a metal. This flag should only be activated in the context of transport (conductivity or resistivity) calculations. In that case use a Fermi-Dirac distribution.

Back to Top

band_plot

Type

LOGICAL

Default

.false.

Description

Writes files for band structure and phonon dispersion plots. The k-path and q-path is provided using filkf and filqf.

Back to Top

bands_skipped

Type

CHARACTER

Default

''

Description

List of bands to exclude from the wannierization, where the number of excluded bands should be smaller or equal to nbndskip. For example, bands_skipped = 'exclude_bands = 1:5' means the first 5 bands are excluded from the wannierization.

Back to Top

bfieldx, bfieldy, bfieldz

Type

REAL

Default

0.0

Description

The magnetic field in the x, y and z Cartesian directions in [Tesla].

Back to Top

bnd_cum

Type

INTEGER

Default

1

Description

Band index for which the cumulant calculation is done. For more than one band, you need to perform multiple calculation and add the results together.

Back to Top

broyden_beta

Type

REAL

Default

0.7

Description

Mixing factor for Broyden mixing scheme.

Back to Top

broyden_ndim

Type

INTEGER

Default

8

Description

Number of iterations used in the Broyden mixing scheme.

Back to Top

carrier

Type

LOGICAL

Default

.false.

Description

If .true. it computes the intrinsic electron or hole mobility such that the carrier concentration is given by ncarrier.

Back to Top

conv_thr_iaxis

Type

REAL

Default

1.d-05

Description

Convergence threshold for iterative solution of imaginary-axis Eliashberg equations.

Back to Top

conv_thr_racon

Type

REAL

Default

5.d-05

Description

Convergence threshold for iterative solution of the analytic continuation of Eliashberg equations from imaginary- to real-axis.

Back to Top

conv_thr_raxis

Type

REAL

Default

5.d-04

Description

Convergence threshold for iterative solution of real-axis Eliashberg equations.

Back to Top

cumulant

Type

LOGICAL

Default

.false.

Description

If .true. calculates the electron spectral function using the cumulant expansion method. Can be used as independent postprocessing by setting ep_coupling =.false.

Back to Top

degaussq

Type

REAL

Default

0.05

Description

Smearing for sum over q in the e-ph coupling in [meV]

Back to Top

degaussw

Type

REAL

Default

0.025

Description

Smearing in the energy-conserving delta functions in [eV]

Back to Top

delta_approx

Type

LOGICAL

Default

.false.

Description

If .true. the double delta approximation is used to compute the phonon self-energy.

Back to Top

delta_qsmear

Type

REAL

Default

0.05

Description

Change in the energy for each additional smearing in the a2f in [meV].

Back to Top

delta_smear

Type

REAL

Default

0.01

Description

Change in the energy for each additional smearing in the phonon self-energy in [eV]

Back to Top

dvscf_dir

Type

CHARACTER

Default

‘./’

Description

Directory where ‘prefix.[dvscf|dyn]_q??’ files are located.

Back to Top

do_CHBB

Type

LOGICAL

Default

.false.

Description

Use CHBB theory for optical absorption calculation.

Back to Top

efermi_read

Type

LOGICAL

Default

.false.

Description

If .true. the Fermi energy is read from the input file.

Back to Top

eig_read

Type

LOGICAL

Default

.false.

Description

If .true. then read a set of eigenvalues from ksdata.fmt. Can be used to read GW (or other) eigenenergies. The code expect a file called “prefix.eig” to be read. One need to provide the same number of bands as in the nscf calculations and all k-points.

Back to Top

elecselfen

Type

LOGICAL

Default

.false.

Description

Calculate the electron self-energy from the el-ph interaction

Back to Top

eliashberg

Type

LOGICAL

Default

.false.

Description

If .true. solve the Eliashberg equations and/or calculate the Eliashberg spectral function.
1) if laniso =.true., the anisotropic Eliashberg equations are solved. This requires that .ephmat, .freq, .egnv, .ikmap files are read from the disk. The files are written when ephwrite =.true. in the input file (see ephwrite variable).
2) if liso =.true., the isotropic Eliashberg equations are solved. This requires that either (a) .ephmat, .freq, .egnv, .ikmap files (see ephwrite variable) or (b) isotropic Eliashberg spectral function file (see fila2f variable) are read from the disk.
3) if .not. laniso and .not. liso , the Eliashberg spectral function is calculated. This requires that .ephmat, .freq, .egnv, .ikmap files are read from the disk. The files are written when ephwrite =.true. in the input file (see ephwrite variable).
Note: To reuse .ephmat, .freq, .egnv, .ikmap files obtained in a previous run, one needs to set ep_coupling =.false., elph =.false., and ephwrite =.false. in the input file.

Back to Top

elph

Type

LOGICAL

Default

.false.

Description

If .true. calculate e-ph coefficients.

Back to Top

ep_coupling

Type

LOGICAL

Default

.true.

Description

If .true. run e-ph coupling calculation.

Back to Top

epbwrite, epbread

Type

LOGICAL

Default

.false.

Description

If epbwrite = .true., the electron-phonon matrix elements in the coarse Bloch representation and relevant data (dyn matrices) are written to disk. If epbread = .true. the above quantities are read from the ‘prefix.epb’ files. Pool dependent files.

Back to Top

epexst

Type

LOGICAL

Default

.false.

Description

If .true. then prefix.epmatwp files are already on disk (don’t recalculate). This is a debugging parameter.

Back to Top

ephwrite

Type

LOGICAL

Default

.false.

Description

Writes 4 files (in prefix.ephmat directory) that are required when solving the Eliashberg equations. ‘ephmatXX’ (XX: pool dependent files) files with e-ph matrix elements within the Fermi window (fsthick) on fine k and q meshes on the disk, ‘freq’ file contains the phonon frequencies, ‘egnv’ file contains the eigenvalues within the Fermi window, and ‘ikmap’ file contains the index of the k-point on the irreducible grid within the Fermi window. These files are required to solve the Eliashberg equations when eliashberg = .true.. The files can be reused for subsequent evaluations of the Eliashberg equations at different temperatures. ephwrite doesn’t work with random k- or q-meshes and requires nkf1,nkf2,nkf3 to be multiple of nqf1,nqf2,nqf3.

Back to Top

epmatkqread

Type

LOGICAL

Default

.false.

Description

If .true. restart an IBTE calculation from scattering written to files.

Back to Top

eps_acustic

Type

REAL

Default

5.d0

Description

The lower boundary for the phonon frequency in el-ph and a2f calculations in [cm-1].

Back to Top

epsiHEG

Type

REAL

Default

0.25d0

Description

Dielectric constant at zero doping for electron-plasmon.

Back to Top

epwread

Type

LOGICAL

Default

.false.

Description

If epwread = .true., the electron-phonon matrix elements in the coarse Wannier representation are read from the ‘epwdata.fmt’ and ‘XX.epmatwpX’ files. Each pool reads the same file. It is used for a restart calculation and requires kmaps = .true. A prior calculation with epwwrite = .true is also required.

Back to Top

epwwrite

Type

LOGICAL

Default

.true.

Description

If epwwrite = .true., the electron-phonon matrix elements in the coarse Wannier representation and relevant data (dyn matrices) are written to disk. Each pool reads the same file.

Back to Top

etf_mem

Type

INTEGER

Default

1

Description

If etf_mem = 1, then all the fine Bloch-space el-ph matrix elements are stored in memory (faster). When etf_mem = 1, more IO (slower) but less memory is required. When etf_mem = 2, an additional loop is done on mode for the fine grid interpolation part. This reduces the memory further by a factor “nmodes”. The etf_mem = 3 is like etf_mem = 1 but the fine k-point grid is generated with points within the fsthick window using k-point symmetry (mp_mesh_k = .true. is needed) and the fine q-grid is generated on the fly. The option etf_mem = 3 is used for transport calculations with ultra dense fine momentum grids.

Back to Top

fermi_diff

Type

REAL

Default

1.d0

Description

Difference between Fermi energy and band edge (in eV). Only relevant when lscreen = .true.

Back to Top

fermi_energy

Type

REAL

Default

0.d0

Description

Value of the Fermi energy read from the input file in [eV].

Back to Top

fermi_plot

Type

LOGICAL

Default

.false.

Description

If .true., write Fermi surface files (in .cube format which can be plotted with VESTA) on nkf1, nkf2, nqf3.

Back to Top

fila2f

Type

CHARACTER

Default

''

Description

Input file with isotropic Eliashberg spectral function. The file contains the Eliashberg spectral function as a function of frequency in [meV]. This file can only be used to calculate the isotropic Eliashberg equations. In this case *.ephmat, *.freq, *.egnv, and *.ikmap files are not required.

Back to Top

fildvscf

Type

CHARACTER

Default

''

Description

Output file containing deltavscf (not used in calculation)

Back to Top

filkf

Type

CHARACTER

Default

‘./’

Description

File which contains the fine k-mesh or the k-path of electronic states to be calculated for elinterp. Crystal coordinates.

Back to Top

filqf

Type

CHARACTER

Default

‘./’

Description

File which contains the fine q-mesh or the q-path of phonon states to be calculated for phinterp. Crystal coordinates.

Back to Top

filukk

Type

CHARACTER

Default

‘prefix.ukk’

Description

The name of the file containing the rotation matrix U(k) which describes the MLWFs.

Back to Top

filukq

Type

CHARACTER

Default

‘prefix.ukq’

Description

The name of the file containing the rotation matrix U(k+q) which describes the MLWFs.

Back to Top

fixsym

Type

LOGICAL

Default

.false.

Description

If .true. try to fix the symmetry-related issues.

Back to Top

fsthick

Type

REAL

Default

1.d10

Description

Width of the Fermi surface window to take into account states in the self-energy delta functions in [eV]. Narrowing this value reduces the number of bands included in the selfenergy calculations.

Back to Top

gap_edge

Type

REAL

Default

0.d0

Description

Initial guess for the superconducting gap edge if gap_edge .gt. 0.d0 in [eV]. Otherwise the initial guess for the gap is estimated based on the critical temperature found from the Allen-Dynes formula and BCS ratio (2*gap/T_c=3.52)

Back to Top

imag_read

Type

LOGICAL

Default

.false.

Description

If .true. read from file the superdconducting gap and renormalization function on the imaginary-axis at a temperature XX. The required file is ‘prefix.imag_aniso_XX’. The temperature should be specified as temps(1) =XX in the input file. This flag works if limag =.true. and laniso =.true., and can be used to:
(1) solve the Eliashberg equations on the real-axis with lpade =.true. or lacon =.true. starting from the imaginary-axis solutions at temperature XX;
(2) solve the Eliashberg equations on the imaginary-axis at temperatures grater than XX using as a starting point the gap estimated at temperature XX.
(3) write to file the superconducting gap on the Fermi surface in cube format at temperature XX. The output file is ‘prefix.imag_aniso_gap_XX_YY.cube’, where YY is the band number within the chosen energy window during the EPW calculation. The file is written if iverbosity =2.

Back to Top

int_mob

Type

LOGICAL

Default

.false.

Description

If .true. and carrier = .false. it compute the intrinsic mobility such that the electron carrier concentration and hole concentration are the same (only one Fermi level) and give both electron and hole mobility in the same run. If the gap is too big, the number of carrier will be so small that the code will be unstable. If .true. and carrier = .true. it will compute the intrinsic electron and hole mobility with two Fermi level such that the electron and hole carrier concentration is ncarrier.

Back to Top

iterative_bte

Type

LOGICAL

Default

.false.

Description

If .true. it compute the iterative Boltzmann Transport Equation (IBTE) intrinsic mobility such that the electron carrier concentration and hole concentration are the same (only one Fermi level) and give both electron and hole mobility in the same run. If the gap is too big, the number of carrier will be so small that the code will be unstable. If .true. and carrier = .true. it will compute the intrinsic electron and hole mobility with two Fermi level such that the electron and hole carrier concentration is ncarrier. Also see mob_maxiter.
Note that the IBTE can only be solved on a homogeneous grid. You can use k-point symmetry to reduce the computational time with mp_mesh_k.

Back to Top

iverbosity

Type

INTEGER

Default

0

Description

0 = short output
1 = verbose output.
2 = verbose output for the superconducting part only.
3 = verbose output for the electron-phonon part only [mode resolved linewidths etc..].

Back to Top

kerread

Type

LOGICAL

Default

.false.

Description

If .true. read Kp and Km kernels from files .ker when solving the real-axis Eliashberg equations.

Back to Top

kerwrite

Type

LOGICAL

Default

.false.

Description

If .true. write Kp and Km kernels to files .ker when solving the real-axis Eliashberg equations.

Back to Top

kmaps

Type

LOGICAL

Default

.false.

Description

Generate the map k+q –> k for folding the rotation matrix U(k+q). If .true., the program reads ‘prefix.kmap’ and ‘prefix.kgmap’ from file. If .false., they are calculated.
Note that for a restart with epwread =.true., kmaps also needs to be set to true (since the information to potentially calculate kgmaps is not generated in a restart run). However, the files “prefix.kmap” and “prefix.kgmap” themselves are actually not used if epwread=.true. and hence need not actually be there.

Back to Top

lacon

Type

LOGICAL

Default

.false.

Description

If .true. an analytic continuation to continue the imaginary-axis Eliashberg equations to real-axis. This flag requires limag =.true. and lpade =.true.

Back to Top

laniso

Type

LOGICAL

Default

.false.

Description

If .true. solve the anisotropic Eliashberg equations on the imaginary-axis. To solve the equations, *.ephmat, *.freq, *.egnv, and *.ikmap files should be provided. These files are described under ephwrite variable.

Back to Top

lifc

Type

LOGICAL

Default

.false.

Description

If .true. uses the real-space inter-atomic force constant generated by q2r.x. The resulting file must be named “ifc.q2r”. The file has to be placed in the same directory as the dvscf files. In the case of SOC, the file must be named “ifc.q2r.xml” and be in xml format. See asr_typ for the type of acoustic sum rules that can be imposed.

Back to Top

limag

Type

LOGICAL

Default

.false.

Description

If .true. solve the imaginary-axis Eliashberg equations.

Back to Top

lindabs

Type

LOGICAL

Default

.false.

Description

If .true. computes indirect phonon absorption. See the input variables omegamax, omegamin, omegastep and n_r.

Back to Top

liso

Type

LOGICAL

Default

.false.

Description

If .true. solve the isotropic Eliashberg equations on the real- or imaginary-axis. To solve the equations provide either: (1) Eliashberg spectral function file using fila2f variable. (2) *.ephmat, *.freq, *.egnv, and *.ikmap files. These files are described under ephwrite variable.

Back to Top

lpade

Type

LOGICAL

Default

.false.

Description

If .true. Padé approximants to continue the imaginary-axis Eliashberg equations to real-axis. This works with limag =.true.

Back to Top

lphase

Type

LOGICAL

Default

.false.

Description

If .true. then fix the gauge for the interpolated dynamical matrix and electronic Hamiltonian.

Back to Top

lpolar

Type

LOGICAL

Default

.false.

Description

If .true. enable the correct Wannier interpolation in the case of polar material.

Back to Top

lreal

Type

LOGICAL

Default

.false.

Description

If .true. solve the Eliashberg equations directly on the real-axis. Only the isotropic case (liso =.true.) is implemented.

Back to Top

lscreen

Type

LOGICAL

Default

.false.

Description

If .true. the el-ph matrix elements are screened by the RPA or TF dielectric function. See (scr_typ).

Back to Top

lunif

Type

LOGICAL

Default

.true.

Description

If .true. a uniform frequency grid is defined between (wsfc,wscut) for solving the real-axis Eliashberg equations. Works only with lreal =.true.

Back to Top

longrange

Type

LOGICAL

Default

.false.

Description

If .true. only the long-range part of the electron-phonon matrix elements are calculated. Works only with lpolar =.true.

loptabs

Type

LOGICAL

Default

.false.

Description

If .true. optical absorption spectra including phonon-assisted and direct transitions using quasi-degenerate perturbation theory.

Back to Top

len_mesh

Type

INTEGER

Default

1

Description

Number of quasi-degenerate meshgrids for optical absorption spectra using quasi-degenerate perturbation theory.

Back to Top

max_memlt

Type

REAL

Default

2.85d0

Description

Maximum memory that can be allocated per pool in [Gb].

Back to Top

meff

Type

REAL

Default

12.0

Description

Density of state effective mass for electron-plasmon.

Back to Top

mob_maxiter

Type

INTEGER

Default

50

Description

Maximum number of iteration during the IBTE.

Back to Top

mp_mesh_k

Type

LOGICAL

Default

.false.

Description

If .true., fine electronic mesh is in the irr. wedge, else a uniform grid throughout the BZ is used.

Back to Top

mp_mesh_q

Type

LOGICAL

Default

.false.

Description

If .true., fine phonon mesh is in the irr. wedge, else a uniform grid throughout the BZ is used. Not currently in use.

Back to Top

meshnum

Type

INTEGER

Default

1

Description

Final meshgrid to be performed using quasi-degenerate perturbation theory, maximum value:ref:len_mesh - 1, used with start_mesh for restart calculations.

Back to Top

nbndsub

Type

INTEGER

Default

0

Description

Number of wannier functions to utilize.

Back to Top

ncarrier

Type

REAL

Default

1.0d+13

Description

If carrier = .true. then compute the intrinsic mobility with ncarrier concentration (in cm^-3). If ncarrier is positive it will compute the electron mobility and if it is negative it will compute the hole mobility. If int_mob is also .true. then it will compute both the electron and hole mobility, which is the recommended way to compute mobility.

Back to Top

nc

Type

REAL

Default

4.0d0

Description

Number of carriers per unit cell that participate to the conduction in the Ziman’s resistivity formula. Typically this corresponds to the number of bands crossing the Fermi level. This can be a fractional number.

Back to Top

nel

Type

REAL

Default

0.01

Description

Carrier concentration for electron-plasmon.

Back to Top

nest_fn

Type

LOGICAL

Default

.false.

Description

Calculate the electronic nesting function.

Back to Top

ngaussw

Type

INTEGER

Default

1

Description

Smearing type for FS average after Wannier interpolation

Back to Top

nk1, nk2, nk3

Type

INTEGER

Default

0

Description

Dimensions of the coarse electronic grid, corresponds to the nscf calculation and wfs in the outdir.

Back to Top

nkf1, nkf2, nqf3

Type

INTEGER

Default

0

Description

Dimensions of the fine electron grid, if filkf is not given.

Back to Top

nq1, nq2, nq3

Type

INTEGER

Default

0

Description

Dimensions of the coarse phonon grid, corresponds to the nqs list.

Back to Top

nqf1, nqf2, nqf3

Type

INTEGER

Default

0

Description

Dimensions of the fine phonon grid, if filqf is not given.

Back to Top

npade

Type

INTEGER

Default

90

Description

Percentage of Matsubara points used in Padé continuation.

Back to Top

nqsmear

Type

INTEGER

Default

10

Description

Number of different smearings used to calculate the a2f.

Back to Top

nqstep

Type

REAL

Default

500

Description

Number of steps used to calculate the a2f

Back to Top

n_r

Type

REAL

Default

1.0

Description

Refractive index used when lindabs = .true.

Back to Top

nsiter

Type

INTEGER

Default

40

Description

Number of iteration for the self-consistency cycle when solving the real- or imaginary-axis Eliashberg equations.

Back to Top

nsmear

Type

INTEGER

Default

1

Description

Number of different smearings used to calculate the phonon self-energy.

Back to Top

nstemp

Type

INTEGER

Default

1

Description

Number of temperature points used for superconductivitiy, transport, indabs, etc.. If nstemp is left blank, or is equivalent to the number of entries in temps(:), then the temperatures provided in temps(:) are used. If nstemp>2 and only two temperatures are given in temps(:), then an evenly spaced temperature grid with steps between points given by (temps(2) - temps(1)) / (nstemp-1) is generated. This grid contains nstemp points. nstemp cannot be larger than 50.

Back to Top

nswi

Type

INTEGER

Default

0

Description

Number of frequency grid points when solving the imaginary-axis Eliashberg equations. If nswi > 0, wscut is ignored. Works only with limag =.true.

Back to Top

nswc

Type

INTEGER

Default

0

Description

Number of frequency grid points between (wsfc, wscut) when solving the real-axis Eliashberg equations. Works only with lreal=.true.

Back to Top

nswfc

Type

INTEGER

Default

0

Description

Number of frequency grid points between (0, wsfc) when solving the real-axis Eliashberg equations. Works only with lreal =.true.

Back to Top

nq_init

Type

INTEGER

Default

-1

Description

Phonon occupation for quasi-degenerate perturbation theory, -1 for Bose-Einstein, -2 for integer Bose-Einstein, -3 for Monte-Carlo method of integration.

Back to Top

muc

Type

REAL

Default

0.d0

Description

Effective Coulomb potential used in the Eliashberg equations.

Back to Top

nw

Type

INTEGER

Default

10

Description

Number of bins for frequency scan in delta( e_k - e_k+q - w).

Back to Top

nw_specfun

Type

INTEGER

Default

100

Description

Number of bins for frequency in electron spectral function.

Back to Top

omegamax

Type

REAL

Default

10

Description

Photon energy maximum (in eV) when lindabs = .true.

Back to Top

omegamin

Type

REAL

Default

0

Description

Photon energy minimum (in eV) when lindabs = .true.

Back to Top

omegastep

Type

REAL

Default

1

Description

Steps in photon energy (in eV) when lindabs = .true.

Back to Top

outdir

Type

CHARACTER

Default

‘./’

Description

Scratch directory.

Back to Top

phonselfen

Type

LOGICAL

Default

.false.

Description

Calculate the phonon self-energy from the el-ph interaction.

Back to Top

plselfen

Type

LOGICAL

Default

.false.

Description

Calculate the electron-plasmon self-energy (model). It requires the definition of nel, meff and epsiHEG.

Back to Top

prefix

Type

CHARACTER

Default

‘pwscf’

Description

Prepended to input/output filenames. Must be the same used in the calculation of the wfs and phonons.

Back to Top

prtgkk

Type

LOGICAL

Default

.false.

Description

Allows to print the electron-phonon vertex |g| (in meV) for each q-point, k-point, i-band, j-band and modes.
Note: Average over degenerate i-band, j-band and modes is performed but not on degenerate k or q-points.
Warning: this produces huge text data in the main output file and considerably slows down the calculation.
Suggestion: Use only 1 k-point (like Gamma).

Back to Top

pwc

Type

REAL

Default

1.0

Description

Power used to define a non-uniform grid between (wsfc, wscut) when solving the real-axis Eliashberg equations. Works only if lreal =.true.

Back to Top

QD_bin

Type

REAL

Default

0.1

Description

Size of many-body meshgrid for quasi-degenerate perturbation theory (in eV).

Back to Top

QD_min

Type

REAL

Default

0.0

Description

Starting energy for quasi-degenerate perturbation theory (in eV).

Back to Top

rand_nq, rand_nk

Type

INTEGER

Default

1

Description

number of random q,k-vectors on the fine mesh

Back to Top

rand_q, rand_k

Type

LOGICAL

Default

.false.

Description

q/k-vectors on the fine mesh are generated randomly

Back to Top

restart

Type

LOGICAL

Default

.false.

Description

Create a restart point every restart_step q-points from the fine grid during the interpolation stage.

Back to Top

restart_filq

Type

CHARACTER

Default

''

Description

Input file to restart from an exisiting q-file. Use to merge different q-grid scattering rates.

Back to Top

restart_step

Type

INTEGER

Default

100

Description

Frequency of restart points during the fine q-grid interpolation phase. This produces restart files called XXX.sigma_restart1

Back to Top

scr_typ

Type

INTEGER

Default

0

Description

If 0 calculates the Lindhard screening, if 1 the Thomas-Fermi screening. Only relevant if lscreen = .true.

Back to Top

scatread

Type

LOGICAL

Default

.false.

Description

If .true. the current scattering rate file is read from file.

Back to Top

scattering

Type

LOGICAL

Default

.false.

Description

If .true. computes scattering rates. See also scattering_serta for the type of scattering.

Back to Top

scattering_serta

Type

LOGICAL

Default

.false.

Description

If .true. computes scattering rates in the self-energy relaxation time approximation. See S. Poncé, E. R. Margine and F. Giustino, Phys. Rev. B 97, 121201 (2018) for more information.

Back to Top

scattering_0rta

Type

LOGICAL

Default

.false.

Description

If .true. then the scattering rates are calculated using 0th order relaxation time approximation.

Back to Top

scissor

Type

REAL

Default

0.0

Description

Gives the value of the scissor shift of the gap (in eV).

Back to Top

selecqread

Type

LOGICAL

Default

.false.

Description

If .true. then restart from the selecq.fmt file

Back to Top

smear_rpa

Type

REAL

Default

0.05d0

Description

Smearing for the calculation of the Lindhard function (in eV). Only relevant if lscreen = .true.

Back to Top

specfun_el

Type

LOGICAL

Default

.false.

Description

Calculate the electron spectral function from the e-ph interaction. The relevant variables in this case are wmin_specfun, wmax_specfun and nw_specfun.

Back to Top

specfun_ph

Type

LOGICAL

Default

.false.

Description

Calculate the phonon spectral function from the e-ph interaction. The relevant variables in this case are wmin_specfun, wmax_specfun and nw_specfun.

Back to Top

specfun_pl

Type

LOGICAL

Default

.false.

Description

Calculate electron-plasmon spectral function. The relevant variables in this case are wmin_specfun, wmax_specfun and nw_specfun. See also nel, meff, epsiHEG.

Back to Top

system_2d

Type

CHARACTER

Default

‘no’

Description

‘no’ then 3D bulk materials
‘gaussian’ then the long-range terms include dipoles only and the range separation function is approximated by a Gaussian following Ref. Phys. Rev. B 94, 085415 (2016)
‘dipole_sp’ then the long-range terms include dipoles following PRB 107, 155424 (2023)
‘quadrupole’ then the long-range terms include dipoles and quadrupoles terms following PRL 130, 166301 (2023) and requires the presence of a “quadrupole.fmt” file.
‘dipole_sh’ then the long-range terms include dipoles following [PRB 105, 115414 (2022)]

Back to Top

start_mesh

Type

INTEGER

Default

1

Description

Starting mesh for optical absorption for quasi-degenerate perturbation theory, used with meshnum for restart calculations.

Back to Top

temps

Type

REAL(nstemp)

Default

300.d0 Kelvin

Description

Temperature values used in superconductivitiy, transport, indabs, etc. in kelvin unit. If no temps are provided, temps=300 and nstemp =1. If two temps are provided, with temps(1)<temps(2) and nstemp >2, then temps is transformed into an evenly spaced grid with nstemp points, including temps(1) and temps(2) as the minimum and maximum values, respectively [Ex) nstemp      =   5 temps       = 300 500]. In this case, points are spaced according to (temps(2) - temps(1)) / (nstemp-1). Otherwise, temps is treated as a list, with the given temperatures used directly [Ex) temps    = 17 20 30]. No more than 50 temperatures can be supplied in this way.

Back to Top

tc_linear

Type

LOGICAL

Default

.false.

Description

If .true. linearized Eliashberg eqn. for superconducting transition temperature Tc will be solved.

Back to Top

tc_linear_solver

Type

CHARACTER

Default

‘power’

Description

Algorithm to solve Tc eigenvalue problem. Possible algorithms are ‘power’, and ‘lapack’.

Back to Top

vme

Type

CHARACTER

Default

‘wannier’

Description

if ‘dipole’ then computes the velocity as dipole+commutator = <psi_mk|p+i[V_NL,r]|psi_nk>. If ‘wannier’ then computes the velocity as dH_nmk/dk - i(e_nk-e_mk)A_nmk where A is the Berry connection. Note: Before v5.4, vme = .FALSE. was the velocity in the local approximation as <psi_mk|p|psi_nk>. Before v5.4, vme = .TRUE. was the same as ‘wannier’.

Back to Top

wannierize

Type

LOGICAL

Default

.false.

Description

Calculate the Wannier functions using W90 library calls and write rotation matrix to file ‘filukk’. If .false., filukk is read from disk.

Back to Top

wepexst

Type

LOGICAL

Default

.false.

Description

If .true. then prefix.epmatwe files are already on disk (don’t recalculate). This is a debugging parameter.

Back to Top

wmax

Type

REAL

Default

0.3d0

Description

Max frequency in delta( e_k - e_k+q - w).

Back to Top

wmax_specfun

Type

REAL

Default

0.d0

Description

The upper boundary for the frequency in the electron spectral function in [eV].

Back to Top

wmin

Type

REAL

Default

0.d0

Description

Min frequency in delta( e_k - e_k+q - w).

Back to Top

wmin_specfun

Type

REAL

Default

0.d0

Description

The lower boundary for the frequency in the electron spectral function in [eV].

Back to Top

wscut

Type

REAL

Default

1.d0

Description

Upper limit over frequency integration/summation in the Eliashberg equations in [eV]. For limag =.true., wscut is ignored if the number of frequency points is given using variable nswi.

Back to Top

wsfc

Type

REAL

Default

0.5 * wscut

Description

Intermediate frequency between (0, wscut) in the integration of the real-axis Eliashberg equations in [eV]. Works only with lreal =.true.

Back to Top

auto_projections

Type

LOGICAL

Default

.false.

Description

If .true. then automatically generate initial projections for Wannier90. It requires scdm_proj =.true.

Back to Top

dis_froz_min, dis_froz_max

Type

REAL

Default

-1d3, -0.9d3

Description

Window which includes frozen states for Wannier90. See wannier90 documentation.

Back to Top

dis_win_max

Type

REAL

Default

-1d3, 1d3

Description

Maximum value of the outer window. See wannier90 documentation.

Back to Top

iprint

Type

INTEGER

Default

2

Description

Verbosity level of Wannier90 code. See wannier90 documentation.

Back to Top

num_iter

Type

INTEGER

Default

200

Description

Number of iterations passed to Wannier90 for minimization. See wannier90 documentation.

Back to Top

proj(:)

Type

CHARACTER

Default

''

Description

Initial projections used in the Wannier90 calculation. Simple solution is proj(1) = 'random'. See wannier90 documentation.

Back to Top

reduce_unk

Type

LOGICAL

Default

.false.

Description

If .true. then plot Wannier functions on reduced grids.

Back to Top

scdm_entanglement

Type

CHARACTER

Default

‘isolated’

Description

Disentanglement type in the SCDM algorithm.

Back to Top

scdm_mu

Type

REAL

Default

0.d0

Description

Parameter for Wannier functions via SCDM algorithm.

Back to Top

scdm_proj

Type

LOGICAL

Default

.false.

Description

If .true. then calculate MLWFs without an initial guess via the SCDM algorithm.

Back to Top

scdm_sigma

Type

REAL

Default

1.d0

Description

Parameter for Wannier functions via SCDM algorithm.

Back to Top

wannier_plot

Type

LOGICAL

Default

.false.

Description

If .true. then plot Wannier functions.

Back to Top

wannier_plot_list

Type

CHARACTER

Default

''

Description

Field read for parsing Wannier function list.

Back to Top

wannier_plot_radius

Type

REAL

Default

3.5d0

Description

Cut-off radius for plotting Wannier functions.

Back to Top

wannier_plot_scale

Type

REAL

Default

1.0d0

Description

Scaling parameter for cube files.

Back to Top

wannier_plot_supercell

Type

INTEGER(3)

Default

(/5,5,5/)

Description

Size of supercell for plotting Wannier functions

Back to Top

wdata(:)

Type

CHARACTER

Default

''

Description

Any extra inforumation to be used in the Wannier90 calculation should be included here. These characters will be written to the ‘prefix.win’ file. For example to plot the first Wannier function in xcrysden format:
—————————————————–
wdata(1) = 'wannier_plot = true'
wdata(2) = 'wannier_plot_list : 1'
—————————————————–
See wannier90 documentation.

Back to Top

plrn

Type

LOGICAL

Default

.false.

Description

If .true. polaron calculations are activated.

Back to Top

type_plrn

Type

INTEGER

Default

-1

Description

Polaron type, -1 for electron polaron and 1 for hole polaron.

Back to Top

init_plrn

Type

INTEGER

Default

1

Description

Method to initialize the polaron wavefunction in the self-consistent loop. 1 for Gaussian wave function initialization (see init_sigma_plrn). 6 for fixed atomic displacement configuration \(\{\Delta \tau_{\kappa\alpha p}\}\) initialization (see init_ntau_plrn).

Back to Top

init_sigma_plrn

Type

REAL

Default

4.6

Description

Width (in bohr) of Gaussian initialization wave function, \(A_{n\mathbf{k}} = \exp(-\sigma_p|\mathbf{k}-\mathbf{k}_0|)\), where \(\mathbf{k}_0\) is given by init_k0_plrn.

Back to Top

init_k0_plrn

Type

REAL, DIMENSION(3)

Default

:math: mathbf{k}_{mathrm{CBM/VBM}}

Description

:math: mathbf{k}-point (in crystal coordinates) in which the initialization Gaussian wave packet is centered.

Back to Top

init_ntau_plrn

Type

INTEGER

Default

1

Description

Number of atomic displacements configurations to be considered if init_plrn =6. If init_ntau_plrn=1, the displacements are read from the dtau_disp.plrn file. If init_ntau_plrn=N>1, the displacements are read from the dtau_disp.plrn_i, where i=1, …, N, files.

Back to Top

conv_thr_plrn

Type

REAL

Default

1.0d-5

Description

The converge threshold in the ab initio polaron equations (in bohr). The self-consistency is achieved when \(\max|\Delta \tau^{\mathrm{save}}_{\kappa\alpha p} - \Delta \tau_{\kappa\alpha p}| < \varepsilon_\mathrm{scf}\).

Back to Top

niter_plrn

Type

INTEGER

Default

50

Description

The maximum number of iterations in the self-consistent loop in the ab initio polaron equations.

Back to Top

ethrdg_plrn

Type

REAL

Default

1.0d-6

Description

Converge threshold (in Ry) in the diagonalization of the effective polaron Hamiltonian.

Back to Top

adapt_ethrdg_plrn

Type

LOGICAL

Default

.false.

Description

If .true. the adaptive diagonalization threshold for the effective polaron Hamiltonian is activated.

Back to Top

init_ethrdg_plrn

Type

REAL

Default

1.0d-2

Description

Initial coarse threshold (in Ry) to be considered in the diagonalization of the effective polaron Hamiltonian.

Back to Top

nethrdg_plrn

Type

INTEGER

Default

11

Description

Number of adaptive diagonalization thresholds to be considered, in logarithmic steps, until reaching final ethrdg_plrn.

Back to Top

io_lvl_plrn

Type

INTEGER

Default

0

Description

I/O level of polaron calculations. If io_lvl_plrn=1, write/read electron-phonon matrix elements to file. If io_lvl_plrn=0, keep them in memory.

Back to Top

restart_plrn

Type

LOGICAL

Default

.false.

Description

If .true. self-consistent solution of polaron equations is skipped and post-processing calculations are activated.

Back to Top

interp_Bqu_plrn

Type

LOGICAL

Default

.false.

Description

If .true. \(B_{\mathbf{q}\nu}\) is interpolated into the fine q-grid or path.

Back to Top

interp_Ank_plrn

Type

LOGICAL

Default

.false.

Description

If .true. \(A_{n\mathbf{k}}\) is interpolated into the fine k-grid or path.

Back to Top

cal_psir_plrn

Type

LOGICAL

Default

.false.

Description

If .true. the real-space polaron wavefunction \(\Psi(\mathbf{r})\) is calculated (see step_wf_grid_plrn). Output file is written in .xsf format (psir_plrn.xsf).

Back to Top

step_wf_grid_plrn

Type

INTEGER

Default

1

Description

Write \(\Psi(\mathbf{r})\) only in every step_wf_grid_plrn grid point of the original grid, given by the Wannier function .cube files.

Back to Top

scell_mat_plrn

Type

LOGICAL

Default

.false.

Description

If .true. the non-diagonal supercell calculation is activated for polarons.

Back to Top

scell_mat

Type

INTEGER, DIMENSION(3, 3)

Default

(/ (/1, 0, 0/), (/0, 1, 0/), (/0, 0, 1/) /)

Description

Transformation matrix :math: S from the unit cell to the (in general non-diagonal) supercell. :math: vec{a}_{s} = S vec{a}_p, where vec{a}_{s} and vec{a}_{p} indicate supercell and the unit cell lattice vectors, respectively.

Back to Top

ZG.x and disca.x input flags are provided in this link.